Response of land use and landscape pattern changes to the evolution of water and sediment in the Beiluo River Basin

Abstract：BackgroundInvestigating the response mechanisms of land use types and landscape pattern indices to water-sediment dynamics is critical for ecosystem management in watersheds. The study area, the Beiluo River Basin, serves as a pivotal ecological transition zone. Systematically analyzing the regulatory effects of land use pattern evolution and landscape heterogeneity characteristics on hydrological processes and sediment transport mechanisms in this basin not only elucidates ecosystem evolution principles but also provides indispensable scientific insights for land use planning, landscape pattern optimization, and ecological conservation. These findings hold practical significance for advancing regional ecological restoration and high-quality development. MethodsThis study adopted a multi-source data fusion and spatial analysis approach to reveal the spatiotemporal evolution of land use and landscape patterns in the Beiluo River Basin over the past three decades, while quantitatively resolving their intrinsic response mechanisms to water-sediment dynamics. Data processing and analysis were conducted using ArcGIS 10.8, Fragstats, and Origin. Long-term observational data on runoff and sediment load from multiple hydrological stations within the basin were integrated. Pearson correlation analysis was employed to quantify correlations between land use types, landscape pattern indices, and water-sediment variables. Regression models were further constructed to elucidate their quantitative relationships. The influence mechanisms of land use and landscape patterns on water-sediment dynamics were comprehensively analyzed across spatial and temporal dimensions. ResultsThe results indicate that the land use structure of the Beiluo River Basin is dominated by grassland (41.94%), forestland (33%), and cropland (25.24%). From 1990 to 2023, significant land use changes occurred: cropland area decreased by 695.26 km², while forestland and grassland areas increased by 494 km², reflecting the substantial outcomes of ecological cropland retirement and vegetation restoration initiatives. Landscape pattern indices revealed that the patch density (PD) and interspersion and juxtaposition index (IJI) of cropland and forestland significantly increased, while the mean patch area (AREA_MN) and largest patch index (LPI) of grassland improved. Correlation analysis demonstrated a significant positive correlation between cropland and sediment load (p<0.05), whereas grassland exhibited a significant negative correlation with sediment load (p<0.05), highlighting the role of grassland vegetation in reducing soil erosion and sediment transport. The correlation between grassland and runoff was relatively weak. Additionally, runoff and sediment load showed a significant positive correlation (R²=0.61), suggesting that other factors, such as topography, soil texture, and human activities, partially attenuated the responsiveness of sediment load to runoff. ConclusionsThis study confirms that enhancing the landscape dominance and structural complexity of forest-grass ecosystems significantly contributes to sediment reduction in the watershed. A strong correlation exists between sediment load and land use/landscape patterns in the Beiluo River Basin. The increasing landscape dominance of forestland and grassland, coupled with their diversifying and complexifying internal structures, has effectively strengthened vegetation-mediated soil stabilization, thereby markedly reducing sediment transport. These findings provide a robust scientific basis for land use planning, landscape pattern optimization, and ecological conservation in the Beiluo River Basin. They support the formulation of precise ecological restoration strategies to promote sustainable regional ecosystem development, synergize ecological and economic benefits, and offer transferable theoretical and practical insights for ecological restoration and governance in the Loess Plateau and other ecologically vulnerable regions globally. Keywords: Beiluo River basin; land use; landscape pattern; water and sediment